I. Field of the Invention
The present invention relates generally to the field of hollow metal fabrication, and more particularly to a method and apparatus for adding grout to hollow metal.
II. Description of the Related Art
Hollow metal manufacturing typically includes the construction of hollow metal components such as doors, door frames, window frames and the like. Hollow metal products are used commercially for sturdy structures such as office buildings. Commonly, hollow metal products are also used in the construction of prisons and other detention facilities where sturdy frames and doors are important for security. In addition to frames and doors, pre-fabricated prison cells are also constructed.
Typically, when a frame is built into a prison or detention facility structure, the hollow metal frame has a hole cut near the top of the frame and grout or cement is poured into the frame to provide further sturdiness to the structure. However, when the grout is added to the frame, the construction on the frame is typically not complete. Hinges, strikes, locks NAME OTHER COMPONENTS and other components have not yet been added to the frame. The frame typically includes screw holes and other apertures for receiving these components.
Grout guards are commonly added to the inside of the frame in order to maintain an airspace so that when the components are screwed onto the frame, there is no resistance from hardened grout. FIG. 1A illustrates a prior art grout guard 100 that is representative of the type of grout guard presently used. The grout guard 100 is affixed in the interior of a hollow metal door frame 105. Typically a hinge reinforcement 110 is placed between the grout guard 100 and frame 105 in order to provide further support for the door hinge (not shown). Having the grout guard 100 affixed to the frame 105, grout is prevented from entering the air space in which screws enter when the hinge is attached. FIG. 1B illustrates another example of a hollow metal frame 120 having a prior art grout guard 125. The grout guard 125 is shown affixed to the frame 120. An air space is maintained to prevent grout from entering the are in which a strike plate (not shown) is affixed to the frame 120.
Often, the addition of these grout guards adds significant labor to the manufacture of hollow metal frames. The metal boxes also typically increase the material cost of the frame.
In accordance with the present invention and the contemplated problems which have and continue to exist in this field, the invention features a method and apparatus for maintaining the necessary air space for components in hollow metal frames while reducing the material cost of the frame and the labor associated with manufacturing the frame.
In general, in one aspect, the invention features an apparatus including substantially planar body having an upper surface and a lower surface, at least one grip connected to the upper surface and a plurality of air space retainers connected to and substantially perpendicular to the lower surface.
In an implementation, the apparatus also includes a substantially planar gasket having a first and second surface, wherein the first surface is in contact with the lower surface of the planar body, and wherein the air space retainers protrude from the second surface of the gasket.
In another implementation, the air space retainers is a substantially cylindrical rod having a first radius.
In another implementation, each cylindrical rod includes a gasket ring wrapped along the circumference of the rods, each ring having an outer radius larger than the first radius, wherein the ring is located at a point along the rod at a length measured from the lower surface of the body.
In another implementation, the cylindrical rod has a third radius located at a point along the rod where the rod intersects the body, wherein the third radius is greater than the first radius.
In another aspect, the invention features a grout guard including a substantially planar body having an upper surface and a lower surface at least one grip connected to the upper surface, a gasket connected to the lower surface and a plurality of cylindrical protrusions connected to and substantially perpendicular to the lower surface and to the gasket the protrusions each having a circular ring gasket around the circumference of the protrusions.
In yet another aspect, the invention features a grout guard kit including a hollow metal frame, a grout guard adapted to be attached and removed from the hollow metal frame and grout adapted to be added to the interior of the hollow metal frame.
In an implementation, the grout guard includes a substantially planar body having an upper surface and a lower surface, at least one grip connected to the upper surface, a gasket connected to the lower surface and a plurality of cylindrical protrusions connected to and substantially perpendicular to the lower surface and to the gasket.
In still another aspect, the invention features a method of manufacturing including forming a hollow metal frame, connecting one or more grout guards to one or more areas of the frame where components are to be added, adding grout to the interior of the frame and removing the grout guards after the grout hardens.
In an implementation, the grout guard is used only one time and disposed.
In another aspect, the invention features a method of installing a hollow metal frame including placing a hollow metal frame, attaching one or more grout guards to areas of the frame where components are to be added, adding grout to the interior of the frame, removing the grout guard when the grout hardens and adding the components to the frame.
One advantage of the apparatus is that the materials used in the manufacture of the apparatus and the material used to install the apparatus is less expensive than prior art grout guards.
Another advantage is that minimal necessary air spaces are maintained in the appropriate areas of hollow metal frames without the interference of larger bulkier grout guards.
Another advantage is that once the grout has hardened, the grout guard can be permanently removed from the frame and disposed.
Another advantage of the invention is that the air spaces created by the grout guard create a further aperture for screws to enter, providing further support for the threads of the screws.